1. Technical Field
The present invention relates to a projector and, more specifically, to a technology of a projector having an ejector pump for cooling a heat source.
2. Related Art
The temperature of a light source apparatus used in a projector rises to a very high temperature such as 800° C. to 1000° C. The projector includes an optical element which modulates light emitted from the light source apparatus. The optical element also generates heat by being irradiated with the light from the light source apparatus and rises in temperature to a level higher than the ambient temperature (for example, to 60° C. to 90° C.). Therefore, an air-cooled cooling system which blows air to the light source apparatus or the like with a fan is employed in order to cool the light source apparatus or the optical element.
Since the temperature of the light source apparatus is very high, the temperature difference from an outside air is large. Therefore, a high cooling efficiency is expected only by blowing air at the ambient temperature to the light source apparatus. In contrast, since the temperature of the optical element is not as high as the light source apparatus, a high cooling efficiency can hardly be obtained even by blowing the air in the same manner as the light source apparatus.
Although the cooling efficiency of the optical element is increased by increasing the airflow quantity of the fan, there arises a problem such that the driving noise of the fan is increased in association with increase in airflow quantity. Accordingly, a technology to increase the cooling efficiency of the optical element by providing a cooling apparatus having a compressor without depending on the increase in airflow quantity of the fan is disclosed in, for example, JP-A-2008-112094.
Also, as a technology to absorb heat generated by the light source apparatus or light in an infrared region, a device having a coolant flow channel on a rear face of a reflector of the light source apparatus is proposed in, for example, JP-A-2005-331743. Also, a device directly arranged with liquid-phase coolant on the rear face of the reflector is proposed in, for example, JP-A-2002-107825.
However, when the compressor is provided in the projector, there arises a problem such that the projector is upsized due to an installation space of the compressor. Also, there also arises a problem such that an electric power for operating the compressor is separately required.
In addition, when the lifetime of the light source apparatus is ended, it is necessary to replace the light source apparatus. However, if the coolant flow channel is provided or the liquid-phase coolant is directly arranged on the rear face of the reflector of the light source apparatus, the coolant flow channel or the like might hinder the removal of the light source apparatus from the projector. In other words, there arises a problem such that the coolant flow channel or the like provided on the rear face of the reflector hinders easy replacement of the light source apparatus when replacing the light source apparatus.